Maternal Depression Lowers Nursing Infant Weight Gain

A new UCLA Neuropsychiatric Institute study suggests that maternal depression, not antidepressant use, affects infant weight gain in the first six months after birth. The study is the first to compare the impact of maternal depression vs. antidepressant use on the physical development of nursing infants.

Published in the April edition of the peer-reviewed Journal of Clinical Psychiatry, the study found that exposure to antidepressant medication through breast milk had no effect on infant weight gain compared with national norms calculated by the Centers for Disease Control (CDC).

In contrast, infant exposure to maternal depression lasting two months or more significantly lowered infant weight gain compared with infants of mothers with major depression lasting less than two months and with the CDC norms.

"Women should not hesitate to get treated for postpartum depression, even if it involves the use of antidepressants," said Dr. Victoria Hendrick, lead investigator and director of the institute's Pregnancy and Postpartum Program. "Our study showed no evidence that children's physical development is harmed by exposure to antidepressants through breast milk, whereas there is evidence that children are harmed by exposure to maternal depression.

"Our findings emphasize the importance of screening for depression and treating the disorder in new mothers," added Hendrick, an assistant professor-in-residence of psychiatry and biobehavioral sciences at UCLA's David Geffen School of Medicine. "Less than one-third of women who suffer major depression postpartum actually are identified by medical professionals as depressed. There is a tremendous amount of under-diagnosing and under-treatment."

Depression in the first six months postpartum affects about 12 percent to 15 percent of new mothers. Symptoms include low self-esteem, feelings of inadequacy as a parent, inability to enjoy the baby or usual activities, lack of energy, insomnia even when the baby is sleeping, problems with concentration, and irritability.

The UCLA research team studied 78 breast-feeding mothers and their infants. All of the women were treated for a mood or anxiety disorder with an antidepressant in the six months following pregnancy, gave birth to full-term infants, had no substance or alcohol use disorders and were nonsmokers. The women began taking antidepressants either during pregnancy or within four weeks of giving birth.

The researchers compared the weights of infants of mothers who suffered major depression for less than two months, infants of mothers who suffered major depression for more than two months and normal infant birth weights as calculated by the CDC.

The average six-month weights of infants involved in the study were 7.26 kilograms for girls and 7.93 kilograms for boys, virtually identical to recently published CDC growth data of 7.2 and 7.9, respectively. The average weights of infants of mothers who suffered major depression for less than two months also were comparable.

In contrast, the average six-month weights of infants of mothers who suffered major depression for more than two months were 6.69 kilograms for girls and 7.25 kilograms for boys. This finding holds up even after factoring in medication dosage and infant birth weight.

"One possible explanation is that maternal depression may influence the feeding behaviors of mothers," Hendrick said. "Studies have shown maternal depression at seven weeks postpartum appears to predict a reduced preference for breast-feeding. In addition, maternal variables that may underlie maternal depression, such as family conflict or financial stress, may influence infant weight gain. In addition, maternal depression may influence biological variables in mother's milk."

The National Institute of Mental Health and the National Centers for Research Resources at the National Institutes of Health funded the study.

Study co-authors included Dr. Lynne M. Smith of Harbor-UCLA Medical Center; Sun Hwang and Dr. Lori Altshuler of the UCLA Neuropsychiatric Institute and West L.A. Veterans Administration Medical Center; and Desiree Haynes of the UCLA Neuropsychiatric Institute.

The UCLA Neuropsychiatric Institute is an interdisciplinary research and education institute devoted to the understanding of complex human behavior, including the genetic, biological, behavioral and sociocultural underpinnings of normal behavior, and the causes and consequences of neuropsychiatric disorders.

Online resources:* UCLA Neuropsychiatric Institute: http://www.npi.ucla.edu* David Geffen School of Medicine at UCLA: http://www.medsch.ucla.edu/